Geez, I dunno, I'd say high light with low light plant (+ possibly higher/ other nutrient demands)=brown moss. You've seen what works... + what doesn't...go with what works for your tank
. Lower PO4...so be it if that's the case unless your other plants are unhappy. Each tank can be different, so many variables...I understood alleopathy isn't an issue in most tanks...(I could be wrong though :huh

